Part B-June 2015

CSIR-UGC National Eligibility Test (NET) for Junior Research Fellowship and Lecturer-ship

Part B


This time CSIR does not allow candidates to carry questions with them. We have collected maximum questions from our candidates (memory based).

1.  When bacteria growing at 200C are warmed at 370C, they are most likely to synthesize membrane lipids with more
1.   short chain saturated fatty acids
2.   short chain unsaturated fatty acids
3.   long chain saturated fatty acids
4.   long chain unsaturated fatty acids
Ans: 3
Expln:- Bacterial thermophiles have membrane lipids rich in saturated fatty acids, which make the membrane more rigid and stable at high temperatures because stronger hydrophobic interactions are formed between saturated fatty acids compared with unsaturated ones. [For more details refer Simple Instant Notes].
2. Which one of the following compounds is generally translocated in the phloem ?
1. Sucrose
2. D-Glucose
3. D-Mannose
4. D-Fructose
Expln:- So far as the phloem sap composition is concerned, it is the evident that the phloem is an important path for the translocation of various materials. The major phloem sap components are carbohydrates. Reducing sugars (glucose, fructose) are not found in phloem sap. Sucroseand raffinose are most common. Sorbitol (sugar-alcohol) is transported in cherries and plums. [For more details refer Simple Instant Notes].
3. n order to study the transcription factor TFIIH, it was cloned from a large number of human subjects. Surprisingly, the subjects having mutation in TFIIH, also showed defects in their DNA repair system. Given below are the explanations:Given below are some statements about prokaryotic and eukaryotic mobile genetic elements or transposons.
A.   Most mobile genetic elements in bacteria transpose via an RNA intermediate.
B.   Most mobile genetic elements in bacteria are DNA.
C.   Mobile genetic elements in eukaryotes are only retrotransposons.
D.   Both, RNA and DNA transposons, are found in eukaryotes.

Choose the correct combination.
1.    A and C     2.   B and C    3.   A and D    4.   B and D

Ans:- 4
Expln:- A difference between certain prokaryotic and eukaryotic transposable elements lies in the mechanism of transposition. Some eukaryotic transposable elements transpose through an RNA intermediate; prokaryotic elements do not use an RNA intermediate. [For more details refer Simple Instant Notes].
4.  Which one of the following statments about LEAFY (LFY), a regulatory gene in Arabidopsis thaliana, is correct ?
1.   LEAFY (LFY) is involved in floral meristem identity.
2.   LAEFY (LFY) is involved in leaf expansion.
3.   LEAFY (LFY) is involved in root meristem identity
4.   LEAFY (LFY) is responsible for far-red light mediated seedling growth.
Ans:- 1
Expln:- In Arabidopsis, there are three primary FLIP (floral initiation program) genes called LEAFY, APETALA1 and CAULIFLOWER, whose expression in the inflorescence meristem is required at the earliest stage of floral initiation. All three genes encode transcription factors. In leafy and apetala1 loss-of-function mutants, there is transformation of flowers to inflorescence-like structures, showing that these genes are required for floral development. Conversely, the overexpression of either gene using a strong constitutive promoter results in the conversion of inflorescences into flowers, showing that each gene can independently activate floral development.

More Questions & Answers Refer Simple Instant Notes